1. Field of the Invention
The present invention relates to an image capturing apparatus, a medium type determining apparatus, and an image forming apparatus.
2. Description of the Related Art
Image capturing apparatuses are known that capture an image of patches printed on a print medium by a two dimensional image sensor and convert obtained RGB values of the patches into color specification values in a standard color space, thereby performing the colorimetry of the patches (refer to Japanese Laid-open Patent Publication No. 2012-63270, for example). The image capturing apparatus disclosed in Japanese Laid-open Patent Publication No. 2012-63270 is mounted on a carriage of an image forming apparatus, captures the image of patches printed on a print medium by the image forming apparatus to acquire RGB values, and calculates colorimetric values of the patches by using the RGB values. The colorimetric values of the patches calculated by the image capturing apparatus are used for color adjustment of the image forming apparatus. The color adjustment of the image forming apparatus may be performed by using the RGB values that the image capturing apparatus has obtained from the patches.
Meanwhile, the function to determine the type of print media on which images are printed is a function required for image forming apparatuses. For example, Japanese Laid-open Patent Publication No. 2012-194445 discloses an image forming apparatus having an optical sensor that determines the type of a print medium based on the intensity of specular light from the print medium.
For example, a configuration that receives specular light from a print medium using the two-dimensional image sensor included in the image capturing apparatus disclosed in Japanese Laid-open Patent Publication No. 2012-63270 can achieve a convenient image capturing apparatus that has both the function to perform the colorimetry of patches or the acquisition of RGB values for the color adjustment of the image forming apparatus and the function to determine the type of print media.
However, the image capturing apparatus disclosed in Japanese Laid-open Patent Publication No. 2012-63270 includes a transmission member that transmits light in a casing, and when specular light from a print medium is received by the two-dimensional sensor, it is expected that specular light from the bottom face of the transmission member also enters the two-dimensional sensor. If the optical images of these pieces of specular light overlap one another on a light-receiving face of the two-dimensional sensor, a problem arises in that the specular light from the print medium cannot be accurately detected.
In view of the above circumstances, there is a need to provide an image capturing apparatus, a medium type determining apparatus, and an image forming apparatus that can accurately detect specular light from a subject.